Various technologies exist wherein attachments must be secured, either internally or externally to a reservoir wall constraining a fluid therewithin. Typically, the attachment or attachments must be secured internally within the reservoir.
Illustrative of such technology is U.S. Pat. No. 4,751,060 which is owned by the assignee of rights in the present invention. That particular document illustrates various walls, baffles, and guiderails secured internally within a reservoir defining an extractor. Such a structure can, typically, be used for extracting liquid petroleum by-products from solid granulate tarsands, meat by-products from bulk meats, etc. The reservoir contains a miscella made up of a liquid solvent, either toxic or non-toxic, and the by-product to be extracted.
In any case, however, while the present invention has applicability to a wall oreinted in any direction, such a device is illustrative of pools and/or baths wherein an attachment or attachments are mounted to an inner surface of a generally-vertical, lateral wall defining the reservoir and confining the miscella. A reservoir such as that discussed herein must have a number of characteristics in order to function optimally. These include strength in securing the attachment at the desired location, adequacy in sealing at the point of attachment to minimize, if not fully preclude, leakage, and accessibility to the securing means so that repairs or maintenance can be performed without having to withdraw, for example, a bolt or stud securing the attachment in place without having to drain the reservoir prior to effecting performance of such functions.
A solution devised included passing a stud through an aperture in the wall defining the reservoir and into an internally threaded aperture in the attachment. One or more sealing gaskets were then placed over the externally-extending portion of the stud. Typically, a tetrofluoroethylene gasket was first placed over the exposed portion of the stud and into engagement with an outwardly facing surface of the reservoir-defining wall. A fiber gasket was then placed over the stud in engagement with the tetrofluoroethylene gasket. An acorn nut was employed and tightened down on a distal end of the stud to tighten the washers or gaskets into engagement with the outwardly facing surface of the wall and the attachment into engagement with the inwardly facing surface of the wall.
Such a solution had a number of drawbacks. First, since the aperture in the reservoir-defining wall was typically oblong so that it could be made to register with the internally-threaded aperture in the attachment regardless of where that aperture was disposed because of minor variations in position, high loads frequently resulted in shifting of the gaskets. This had as a consequence the weakening of the seal and inability to support full bolt torque.
In some applications, the reservoir-defining wall and attachment are radiused. This solution was inadequate in view of the fact that, in such applications, leaks resulted.
In view of the fact that the stud was threaded at both ends, it frequently happened that, for example, the stud was threaded too deeply into the internally-threaded aperture in the attachment. As a result, too little threading was available for securing of the acorn nut to the externally-extending end of the stud. Conversely, when inserting the stud into the attachment, too short a portion of the stud was threaded into the attachment in order to ensure availability of adequate threading at the other end to accommodate the acorn nut. In either case, however, the point of attachment had the potential of proving too weak.
Finally, this solution was deficient in another major respect. If there was a leak, the reservoir had to be drained at least to a level below the point of attachment prior to repairing the leak. This was so since, when the acorn nut was unthreaded from the stud, no sealing or attachment was any longer maintained.
A second solution was proposed to effect mounting and sealing of an attachment to the reservoir-defining wall. This included employment of a high-strength bolt having a fiber gasket in engagement with the head thereof, the boss or shank of the bolt being inserted through the aperture in the wall and threaded down into the internally-threaded aperture in the attachment. A 1/2 coupling was, previously, welded to the outwardly-facing surface of the wall at a location to enclose the aperture within the perimeter thereof. After the bolt was tightened down to secure the attachment, the chamber defined within the 1/2 coupling was then closed by employment of a plug which was, typically, threaded into an end of the 1/2 coupling. The chamber defined within the 1/2 coupling was, if desired, sealed by means of a pipe seal compound.
This proposed solution had certain advantages over the solution discussed above. For example, it was able to employ an off-the-shelf bolt, while the stud in the previous solution was, typically, expensive to obtain, particularly if a sophisticated material was used. Additionally, when a high-strength bolt was employed, full load capacity was able to be achieved. As a result, there was less likelihood of shifting or loosening. Finally, the means of securing could be worked upon without disturbing the bolt or load capacity.
Never-the-less, this solution still had certain inherent deficiencies. For example, because the 1/2 coupling was welded to the reservoir-defining wall, certain problems arose. The weld proved costly and subjected the wall to distortion. Additionally, it was difficult to elongate the aperture in the reservoir-defining wall to any significant extent. As will be recalled, such an elongation can be necessary to ensure registration of the aperture with that in the attachment. Furthermore, the 1/2 coupling defined a chamber in which noxious substances might accumulate if sealing was not adequate. When the plug was removed, these substances were free to escape.
It is to these problems and dictates of the prior art that the present invention is directed. It is a fastening structure which addresses these problems and dictates and provides improved means for securing an attachment to an inner surface of a wall confining a fluid therewithin.